introduce configurable default language

- allows the application to declare the default language tag.
- guarantees that build files will always include a language tag.
Merge pull request #1 from ekashida/default-lang

introduce configurable default language. improving lang token detection using regex.
Update HISTORY.md
Update HISTORY.md
clean up readme
update package.json
bump version to 0.0.1
adding support for yrb bundle formats represented by *.pres files
Merge pull request #2 from caridy/master

adding support for yrb bundle formats represented by *.pres files
add unit tests for plugin.js